CN108514999B - Spraying process of water-based bi-component paint - Google Patents
Spraying process of water-based bi-component paint Download PDFInfo
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- CN108514999B CN108514999B CN201810363697.7A CN201810363697A CN108514999B CN 108514999 B CN108514999 B CN 108514999B CN 201810363697 A CN201810363697 A CN 201810363697A CN 108514999 B CN108514999 B CN 108514999B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/04—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases
- B05D3/0406—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases the gas being air
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
Abstract
A spray coating process for an aqueous two-component coating, the spray coating process comprising the steps of: paint mixing and using steps: uniformly mixing the water-based main paint and the curing agent, adding purified water to dilute the mixture to the construction viscosity, filtering the mixture by a screen of 100 meshes and 300 meshes, and standing the filtered mixture for 10 to 30 minutes to obtain a coating to be sprayed; spraying: spraying according to the coating weight of 80-100 g per square meter; and (3) drying: drying for 1-10 hours in an environment with the temperature of 8-35 ℃ and the humidity of below 85%, and drying for 3-8 hours in a drying room after surface drying. The drying step specifically comprises: drying for 1-10 hours in an environment with the temperature of 20-25 ℃ and the humidity of less than 75%, and drying for 4-6 hours in a drying room after surface drying. By selecting a specific process, specific polyurethane without hydroxyl and acrylic acid with low hydroxyl content, the prepared coating has good performance and is not easy to crack, delaminate, whiten and the like.
Description
Technical Field
The invention relates to a spraying process of a water-based bi-component coating.
Background
The double-component water paint has excellent filming performance and is prepared with water polymer polyol and water polyisocyanate as curing agent, and through separate packing and mixing in certain proportion. Wherein the aqueous polymer polyol comprises aqueous polyacrylate polyol, aqueous polyurethane polyol, aqueous polyester polyol and polyether polyol, and mixed polyol. The water-based polyacrylate polyol has the advantages of excellent color retention, light retention and weather resistance, low price, easy adjustment of molecular weight, glass transition temperature (Tg) and hydroxyl content and the like, and is the first choice of water-based polymer polyol in the two-component water-based coating at present.
Emulsion type and dispersion type polyacrylate polyols can be prepared by adopting different polymerization processes. The hydroxyl content of the aqueous polyacrylate dispersoid is high, and the prepared coating film has excellent water resistance and chemical resistance, so that the defects that a large amount of organic solvent is used in the production process, the solid content of the product is low, generally 30-40 percent, the drying speed of the coating film is slow, the cost is high and the like exist. In contrast, emulsion type polyacrylate polyol (also called hydroxyl polyacrylate emulsion) has simple production process, solid content of more than 50 percent, low cost and quick drying speed.
However, the use of aqueous polyacrylate dispersions with higher hydroxyl content results in incomplete dehydration during the spray drying process, which leads to the disadvantages of cracking, delamination, whitening, etc.
Disclosure of Invention
In order to solve the technical problem, the invention provides a spraying process of a water-based two-component coating, which comprises the following steps:
paint mixing and using steps: uniformly mixing the water-based main paint and the curing agent, adding purified water to dilute the mixture to the construction viscosity, filtering the mixture by a screen of 100 meshes and 300 meshes, and standing the filtered mixture for 10 to 30 minutes to obtain a coating to be sprayed;
spraying: spraying according to the coating weight of 80-100 g per square meter;
and (3) drying: drying for 1-10 hours in an environment with the temperature of 8-35 ℃ and the humidity of below 85%, and drying for 3-8 hours in a drying room after surface drying.
The drying step specifically comprises: drying for 1-10 hours in an environment with the temperature of 20-25 ℃ and the humidity of less than 75%, and drying for 4-6 hours in a drying room after surface drying.
The water-based main paint consists of 100 parts by weight of water-based acrylic emulsion containing hydroxyl, 10-50 parts by weight of water-based aliphatic polyurethane dispersoid and 1-20 parts by weight of addition auxiliary agent, wherein the curing agent is isocyanate curing agent, and the hydroxyl content of the water-based acrylic emulsion containing hydroxyl is 0.5-6 wt%.
The hydroxyl-containing aqueous acrylic emulsion is formed by polymerizing a non-functional acrylate monomer, a hydroxyl-containing acrylate monomer and an acrylic monomer in water, and the molecular weight of the hydroxyl-containing aqueous acrylic emulsion is 12000-14000 daltons.
The waterborne aliphatic polyurethane dispersion is obtained by neutralizing a prepolymer obtained by polymerization reaction of aliphatic diisocyanate, polyol and dihydric alcohol containing hydrophilic groups, and the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000-5000 Dalton.
The isocyanate curing agent is selected from one or more of polyethylene glycol modified HDI tripolymer, sulfonic group modified IPDI tripolymer, polyethylene glycol modified IPDI tripolymer, sulfonic group modified HDI tripolymer and biuret of HDI, and the NCO content of the isocyanate curing agent is 19-22 wt%.
The additive is one or more selected from defoaming agent, flatting agent, wetting dispersant, anti-sagging additive and adhesion promoter.
The defoaming agent is selected from one or more of a foam breaking polysiloxane solution, a polyether modified polydimethylsiloxane solution, a mixture of organic silicon-free foam breaking polysiloxane and hydrophobic solids, and a silicon oxide polyether emulsion.
The defoaming agent is selected from polyether modified polydimethylsiloxane solution and silicone-free foam breaking polysiloxane.
The leveling agent is selected from one or more of polyether modified siloxane solution, nonionic acrylic copolymer solution, ionic polyacrylate solution, polyether modified acrylic dimethyl siloxane solution capable of agglomerating, and polyether modified acrylic functional dimethyl siloxane solution.
The wetting and dispersing agent is selected from one or more of a low molecular weight polycarboxylic acid polymer hydroxylammonium salt solution, a polyfunctional polymer alcoholammonium salt solution, a partially neutralized polycarboxylic acid polymer hydrocarbylammonium salt, and a polysiloxane copolymer solution.
The anti-sagging auxiliary agent is selected from one or more of a polyurethane solution, a urea-modified polyurethane solution, and a poly-hydrocarbyl carboxylic acid amide solution.
The adhesion promoter is selected from one or more silane coupling agents selected from gamma-aminopropyltrimethoxysilane, aminopropyltriethoxysilane 3-aminopropyltrimethoxysilane 3-glycidyloxypropyltrimethoxysilane gamma-methacryloxypropyltrimethoxysilane gamma-mercaptopropyltriethoxysilane.
By selecting a specific process, specific polyurethane without hydroxyl and acrylic acid with low hydroxyl content, the prepared coating has good performance and is not easy to crack, delaminate, whiten and the like.
The above-described and other features, aspects, and advantages of the present application will become more apparent with reference to the following detailed description.
Detailed Description
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.
Hydroxyl-containing aqueous acrylic emulsion
The hydroxyl-containing water-based acrylic emulsion is prepared by dispersing a polymer obtained by carrying out free radical polymerization on at least two non-functional (methyl) acrylate monomers, one hydroxyl-containing (methyl) acrylate monomer and one (methyl) acrylic monomer in water through high-speed shearing by using a neutralizing agent; wherein the non-functional (meth) acrylate monomers include at least two of the following monomers: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, t-butyl methacrylate isobornyl (meth) acrylate, the amount being 50-80% by weight of the total amount of the reaction monomers;
the hydroxyl group-containing (meth) acrylate monomer contains at least one of the following monomers: hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate, wherein the dosage of the hydroxyethyl methacrylate, the hydroxypropyl methacrylate and the hydroxypropyl acrylate accounts for 19-40 wt% of the total amount of the reaction monomers;
the (meth) acrylic monomer comprises at least one of the following monomers: methacrylic acid, acrylic acid; the amount is 1-10 wt% of the total amount of the reaction monomers.
The hydroxyl group content of the hydroxyl group-containing aqueous acrylic emulsion is 1 to 6 wt% (based on the solid content of the hydroxyl group-containing aqueous acrylic emulsion); the solid content is 30-60 wt%, and the preferable range is 40-50 wt%; the molecular weight is 6000-; the VOC content is less than 9 wt.% (based on the total amount of the hydroxyl group-containing aqueous acrylic emulsion).
In the invention, the monomers for preparing the acrylic resin at least comprise alkyl hydroxyacrylate and alkyl acrylate, wherein the carbon chain length of the alkyl acrylate is C1-C8, and the carbon chain length of the alkyl methacrylate is C1-C4.
As an example, the alkyl acrylate may be methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, or n-octyl acrylate.
In the present invention, the alkyl acrylate is preferably an alkyl acrylate having a relatively low glass transition temperature, such as n-butyl acrylate.
In one embodiment, the alkyl methacrylate may include one or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate.
When the acrylic resin is copolymerized with a plurality of monomers, the acrylic resin having a specific glass transition temperature can be synthesized by adjusting the kinds of the monomers and the percentage of the monomers in the copolymer. Wherein the glass transition temperature is the temperature at which the polymer changes from a high elastic state to a glassy state, reflecting the conditions for the transition between the elasticity and brittleness of the polymer. Acrylic resins are typical copolymers whose glass transition temperature can be calculated by the Fox equation:
in the above formula, Wi and Tgi are respectively the mass ratio of each monomer i in the copolymer and the glass transition temperature of the homopolymer thereof. The methacrylate and the acrylate monomer are different in that methyl exists in an alpha-position of the methacrylate, the rotation motion of a carbon-carbon main chain is interfered, the methacrylate is a typical asymmetric structure, and the methacrylate can enable molecules of a copolymer to have polarity, so that the glass transition temperature of the methacrylate is higher, and the brittle temperature and the tensile strength of the methacrylate are higher. The addition of methacrylate can improve the physical and mechanical properties of the coating film, so that methacrylate polymers are harder and have better aging resistance than acrylate polymers.
In the present invention, the structure of the modified acrylic resin is preferably an acrylic resin having a small number of branches.
The modified acrylic resin can be prepared by any method known to those skilled in the art. The usual methods are polycondensation, free radical polymerization and hydrosilylation. In the present invention, a radical polymerization method is preferred.
Free radical polymerization is a polymerization reaction initiated by a free radical to continuously grow a chain-growing free radical, and is also called free radical polymerization. Radical polymerization, which is a process of joining a plurality of monomers to form a macromolecule by opening double bonds in the monomer molecules and repeating an addition reaction between the molecules many times. The most commonly used method for generating free radicals is thermal decomposition of the initiator, and the free radicals can also be generated by heating, ultraviolet irradiation, high-energy irradiation, electrolysis, plasma initiation and the like.
Examples of the polymerization initiator include peroxide-based polymerization initiators and azo-based polymerization initiators.
Examples of the peroxide-based polymerization initiator include organic peroxides such as peroxycarbonate, ketone peroxide, peroxyketal, hydrogen peroxide, dialkyl peroxide, diacyl peroxide, and peroxyester.
Examples of the azo polymerization initiator include azo compounds such as 2,2 '-azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), 2 '-azobis (2, 4-dimethylvaleronitrile), and dimethyl 2, 2' -azobisisobutyrate.
Aqueous aliphatic polyurethane dispersions
The waterborne aliphatic polyurethane dispersion is obtained by neutralizing and dispersing a prepolymer, which is obtained by polymerization reaction of aliphatic diisocyanate, polyol and dihydric alcohol containing hydrophilic groups, in water at high speed, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000-5000 daltons, and the content of hydroxyl groups is lower than 0.01 percent.
(1) The aliphatic diisocyanate is selected from one or two or more of HDI, HMDI, IPDI and XDI;
(2) the polyol may be a polyether polyol such as polyethylene glycol, polypropylene glycol, polytetrahydrofuran or mixtures thereof; the polyol used may also be a polyester polyol such as a polyacyladipate polyol, a polycarbonate polyol, a polycaprolactone polyol or a mixture thereof. Preferably polyester polyols, having a molecular weight of 400-;
(3) the dihydric alcohol containing hydrophilic groups comprises one or both of dimethylolpropionic acid (DMPA) and dimethylolbutyric acid (DMBA).
Curing agent
The water dispersible aliphatic polyisocyanate is used as a curing agent and comprises polyethylene glycol or sulfonic acid group modified IPDI tripolymer, HDI tripolymer and/or HDI biuret or a mixture thereof, preferably one or two of polyethylene glycol or sulfonic acid group modified HDI tripolymer or polyethylene glycol or sulfonic acid group modified IPDI tripolymer, and more preferably polyethylene glycol or sulfonic acid group modified HDI tripolymer. The NCO content is 19 to 22 wt.%.
Other auxiliaries
The additive is one or more selected from defoaming agent, leveling agent, wetting dispersant, anti-sagging additive and adhesion promoter.
The defoaming agent is selected from one or more of foam breaking polysiloxane solution, polyether modified polydimethylsiloxane solution, a mixture of foam breaking polysiloxane and hydrophobic solid without organic silicon and silicon oxide polyether emulsion. Wherein the non-volatile part of the foam breaking polysiloxane solution is 15-30%, the non-volatile part of the polyether modified polydimethylsiloxane solution is 50-70%, the non-volatile part of the mixture of the foam breaking polysiloxane solution without organic silicon and the hydrophobic solid is 20-38%, and the non-volatile part of the silicon oxide polyether emulsion is 20-35%.
The defoaming agent is preferably a mixture of polyether modified polydimethylsiloxane solution, defoaming polysiloxane without organic silicon and hydrophobic solid in polyethylene glycol, and the compounding weight ratio is (1-2) to 1.
The leveling agent is selected from one or more of polyether modified siloxane solution, nonionic acrylic copolymer solution, ionic polyacrylate solution, polyether modified acrylic functional group dimethyl siloxane solution and polyether modified acrylic functional group dimethyl siloxane solution, and preferably polyether modified siloxane solution.
The wetting and dispersing agent of the present invention is selected from one or more of a low molecular weight polycarboxylic acid polymer hydroxylammonium salt solution, a polyfunctional polymer alcoholammonium salt solution, a partially neutralized polycarboxylic acid polymer hydrocarbylammonium salt, and a polysiloxane copolymer solution. Wherein the non-volatile part of the low molecular weight polybasic carboxylic acid polymer hydroxyl ammonium salt solution type wetting dispersant is 40-60%, the non-volatile part of the polyfunctional group polymer alcohol ammonium salt solution type wetting dispersant is 30-50%, and the non-volatile part of the partially neutralized polybasic carboxylic acid polymer hydroxyl ammonium salt and the polysiloxane copolymer solution type wetting dispersant is 40-60%; preferred are the olammonium salt solution type wetting dispersants of the multifunctional polymer.
The anti-sagging auxiliary agent is selected from one or more of a polyurethane solution, a urea modified polyurethane solution and a poly-hydrocarbyl carboxylic acid amide solution.
The adhesion promoter is selected from nonionic compound promoters, silane coupling agents, phthalate coupling agents and the like, and preferably silane coupling agents. Wherein the silane coupling agent is one or more selected from gamma-aminopropyltrimethoxysilane aminopropyltriethoxysilane 3-aminopropyltrimethoxysilane 3-glycidyloxypropyltrimethoxysilane gamma-methacryloyloxypropyltrimethoxysilane gamma-mercaptopropyltriethoxysilane.
Hereinafter, the present invention will be described in more detail by way of examples, but it should be understood that these examples are merely illustrative and not restrictive. The starting materials used are all commercially available, unless otherwise stated.
The present invention is described in detail below with reference to several examples.
PTMEG1000 polytetrahydrofuran diol, mitsubishi, molecular weight 1000;
PTMEG2000 polytetrahydrofuran diol, mitsubishi, molecular weight 2000;
PPG2000 polypropylene oxide glycol, shanghai high petrochemical, molecular weight 2000;
PPA2000 poly 1,3 propylene glycol adipate, New Huafeng material, molecular weight 2000;
HDI 1, 6-hexamethylene diisocyanate, Tanbachi, molecular weight 168.08;
BDO 1, 4-butanediol, Mitsubishi chemical, molecular weight 90.12;
DMBA 2, 2-dimethylolbutanoic acid, Jiangxi Red, molecular weight 148.2;
DabcoT-9 stannous octoate, gas chemical industry;
irganox1010 tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propanoic acid ] pentaerythritol ester, basf;
irgafos168 tris (2, 4-di-tert-butylphenyl) phosphite, basf;
tinuvin 3292- (2 '-hydroxy-5' -tert-octylphenyl) benzotriazole, basf;
tinuvin 292 bis (1,2,2,6, 6-pentamethyl-4-piperidinyl) sebacate, basf;
TEA triethylamine, commercially available, chemically pure;
example 1
Heating the A component PTMEG1000, the B component HDI and the C component BDO to 100, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the A component; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 2min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into a mixture containing 50Kg of acetone/water (the mass ratio is 3:2), adding 700g of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 percent by weight, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000 daltons.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.5 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 2
Heating the A component PTMEG1000, the B component HDI and the C component BDO to 100, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the A component; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 6min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 wt%, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 5000 daltons.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.8 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 3
Heating the A component PTMEG1000, the B component HDI and the C component BDO to 100, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the A component; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 2min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 percent by weight, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000 daltons.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 2h, heating to 88-95 ℃, keeping the temperature for 4h after dropwise adding, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 13000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.9 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 4
The same as in example 1 except that 100 parts by weight of the aqueous aliphatic polyurethane dispersion was added.
Example 5
The same as in example 1 except that 5 parts by weight of the aqueous aliphatic polyurethane dispersion was added.
Example 6
The same as in example 1, except that no aqueous aliphatic polyurethane dispersion was added.
Example 7
Heating the A component PTMEG2000, the B component HDI and the C component BDO to 100 ℃, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the A component; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 2min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 wt%, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 7000 Dalton.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.5 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 8
Heating the PPG2000 as the component A, the HDI as the component B and the BDO as the component C to 100, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the component A; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 2min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 wt%, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 8000 Dalton.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.5 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 9
Respectively heating the component A PPA2000, the component B HDI and the component C BDO to 100 ℃, 60 ℃ and 80 ℃, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the component A; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are uniformly mixed in the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of HDI is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1.2: 1, heating to 140 ℃ and 180 ℃, reacting for 5min under the stirring of the rotation speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 percent by weight, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 10000 Dalton.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.5 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Example 10
Heating the A component PTMEG1000, the B component HDI and the C component BDO to 100, 60 and 80 ℃ respectively, and adding 40ppm of DabcoT-9, 0.2 percent of Irganox1010, 0.2 percent of Irgafos168, 0.4 percent of Tinuvin 329 and 0.4 percent of Tinuvin 292 into the A component; adding DMBA with the mass of 1.31 times of that of BDO into the component C, and maintaining the temperature at 80, 60 and 60 ℃ after the three components are fully and uniformly melted;
after A, B, C three components are evenly mixed according to the proportion of 57.7 wt%, 33.4 wt% and 8.9 wt%, part of PTMEG1000 is added so that the molar ratio of NCO groups to OH groups in the mixed solution is 1: 1.2, heating to 140 ℃ and 180 ℃, reacting for 5min under the stirring of the rotating speed of 200rpm, and then carrying out underwater granulation and collection to obtain waterborne polyurethane particles;
and sequentially putting 20Kg of the waterborne polyurethane particles into 50Kg of acetone/water mixture (the mass ratio is 3:2), adding 69.4Kg of TEA, heating to 70 ℃, keeping the temperature for 2h at 200rpm to ensure that the waterborne polyurethane particles are completely emulsified and dispersed, desolventizing, cooling and filtering to obtain a waterborne aliphatic polyurethane dispersion with the solid content of 60.0 percent by weight, wherein the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000 daltons.
Weighing 60-80% of emulsifier, mixing with 70-80% of water, stirring uniformly, adding ethyl acrylate, hydroxyethyl methacrylate and methacrylic acid (the amount is 8wt% of the total amount of the reaction monomers), and stirring uniformly to obtain emulsion for later use;
adding the remaining 20-30% of water and 20-40% of emulsifier into a flask, stirring and dispersing uniformly, heating to 80-90 ℃, adding an initiator, simultaneously dropwise adding the emulsion obtained in the step 1) into the flask for 4-5h, heating to 88-95 ℃ after dropwise adding, preserving heat for 1-2h, cooling to 35-45 ℃, adding ammonia water to adjust the pH value to 7-8, and obtaining the hydroxyl-containing aqueous polypropylene emulsion, wherein the molecular weight of the hydroxyl-containing aqueous polypropylene emulsion is 12000 daltons, and the hydroxyl content of the hydroxyl-containing aqueous polypropylene emulsion is 0.5 wt%.
Adding 1 part by weight of defoaming agent and 20 parts by weight of the aqueous aliphatic polyurethane dispersoid into 100 parts by weight of hydroxyl-containing aqueous acrylic emulsion, and uniformly stirring to obtain the main agent of the aqueous two-component coating.
Spraying process
Paint mixing and using steps: uniformly mixing the weighed water-based main paint and a curing agent (HDI tripolymer modified by polyethylene glycol), adding a certain amount of purified water to dilute to construction viscosity, wherein the mass ratio of the main paint to the curing agent purified water is 100: 15: 10. filtering with 100-mesh and 300-mesh, and standing for 10-30 minutes to obtain the coating to be sprayed;
spraying: spraying the coating to be sprayed on a substrate, wherein the spraying amount is 100-120g/m 2;
and (3) drying: controlling the indoor temperature at 25 ℃ and the humidity below 50-60% to dry to surface dryness, and continuing drying for 24-48 hours after the surface dryness.
The paint film performance is tested according to GB/T23999-2009 waterborne wood coatings for interior decoration, and the surface drying time, the actual drying time, the pencil hardness, the water resistance (35 ℃ and 48 hours), the dry heat resistance (70 ℃ and 96 hours) and the alcohol resistance (50% ethanol water solution and 4 hours) are tested.
It can be seen that the two-component coating of the present invention has very good properties.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. All equivalent changes and modifications made according to the disclosure of the present invention are covered by the scope of the claims of the present invention.
Claims (6)
1. A spray coating process for a water-based two-component coating, comprising the steps of:
paint mixing and using steps: uniformly mixing the water-based main paint and the curing agent, adding purified water to dilute the mixture to the construction viscosity, filtering the mixture by a screen of 100 meshes and 300 meshes, and standing the filtered mixture for 10 to 30 minutes to obtain a coating to be sprayed;
spraying: spraying according to the coating weight of 80-100 g per square meter;
and (3) drying: drying for 1-10 hours in an environment with the temperature of 8-35 ℃ and the humidity of below 85%, and drying for 3-8 hours in a drying room after surface drying;
the water-based main paint consists of 100 parts by weight of water-based acrylic emulsion containing hydroxyl, 10-50 parts by weight of water-based aliphatic polyurethane dispersoid and 1-20 parts by weight of addition auxiliary agent, wherein the curing agent is isocyanate curing agent, and the hydroxyl content of the water-based acrylic emulsion containing hydroxyl is 0.5-6 wt%;
the hydroxyl-containing aqueous acrylic emulsion is formed by polymerizing a non-functional acrylate monomer, a hydroxyl-containing acrylate monomer and an acrylic monomer in water, and the molecular weight of the hydroxyl-containing aqueous acrylic emulsion is 12000-14000 daltons;
the waterborne aliphatic polyurethane dispersion is obtained by neutralizing a prepolymer obtained by polymerization reaction of aliphatic diisocyanate, polyol and dihydric alcohol containing hydrophilic groups, and the molecular weight of the waterborne aliphatic polyurethane dispersion is 4000-5000 Dalton;
the isocyanate curing agent is selected from one or more of polyethylene glycol modified HDI tripolymer, sulfonic group modified IPDI tripolymer, polyethylene glycol modified IPDI tripolymer, sulfonic group modified HDI tripolymer and biuret of HDI, and the NCO content of the isocyanate curing agent is 19-22 wt%.
2. The spray coating process of an aqueous two-component coating according to claim 1, wherein the drying step specifically comprises: drying for 1-10 hours in an environment with the temperature of 20-25 ℃ and the humidity of less than 75%, and drying for 4-6 hours in a drying room after surface drying.
3. The spraying process of the water-based two-component coating as claimed in claim 1, wherein the additive is one or more selected from the group consisting of an antifoaming agent, a leveling agent, a wetting dispersant, an anti-sagging additive, and an adhesion promoter.
4. The process of claim 3, wherein the defoaming agent is selected from one or more of a defoaming polysiloxane solution, a polyether-modified polydimethylsiloxane solution, and a silicone oxide polyether emulsion.
5. The spray coating process of any one of claims 3 or 4, wherein the defoamer is a polyether modified polydimethylsiloxane solution.
6. The spraying process of claim 3, wherein the leveling agent is one or more selected from the group consisting of a polyether modified siloxane solution, a non-ionic acrylic copolymer solution, and an ionic polyacrylate solution.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102108246A (en) * | 2010-12-26 | 2011-06-29 | 华南理工大学 | Double-component polyurethane water-based paint |
| CN102533078A (en) * | 2011-11-30 | 2012-07-04 | 烟台万华聚氨酯股份有限公司 | Water-based coating and preparation method and application thereof |
| CN105086805A (en) * | 2015-09-22 | 2015-11-25 | 佛山市顺德区吕邦化工有限公司 | High-hardness water-borne double-component wood-ware varnish with high wear resistance and preparing method thereof |
| CN105505124A (en) * | 2016-01-15 | 2016-04-20 | 成都优品化工有限公司 | Water-dilutability epoxy woodware transparent primer and preparing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102108246A (en) * | 2010-12-26 | 2011-06-29 | 华南理工大学 | Double-component polyurethane water-based paint |
| CN102533078A (en) * | 2011-11-30 | 2012-07-04 | 烟台万华聚氨酯股份有限公司 | Water-based coating and preparation method and application thereof |
| CN105086805A (en) * | 2015-09-22 | 2015-11-25 | 佛山市顺德区吕邦化工有限公司 | High-hardness water-borne double-component wood-ware varnish with high wear resistance and preparing method thereof |
| CN105505124A (en) * | 2016-01-15 | 2016-04-20 | 成都优品化工有限公司 | Water-dilutability epoxy woodware transparent primer and preparing method thereof |
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